Electric switch.



J. H. GRAVELL.

ELECTRIC SWITCH.

APPLlcArmN FILED une H. 1914.

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I. H. GRAVEU..

ELECTRIC SWTCH.

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- nv /vmn AIToHNErs UNITED STATES PATENT OFFICE.

JAMES H. GRAVELL, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR T HALE AND KILBURN COMPANY, 0F PHILADELPHIA, PENNSYLVANIA, A. CORPORATION OF DELAWARE.

ELECTRIC SWITCH.

Specication of `Letters Patent.y

Patented Oct. 10, 1916.

Application led J une 17, 1914. Serial No.,845,522.

To all whom it may concern.'

Be it known that I, JAMES H. GmvnLL, a citizen of'the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvanla, have invented certain new and useful Improvements in Electric Switches, of which the following is a specification.

M invention relates to electric switches, particularly such as are adapted to be used in connection with electric welding machines.

The object of the invention is to provide a switch of simple and cheap construction, large current carrying characteristics, and` so mechanically arranged that all wearing parts may easily and quickly be replaced.

Other objects of my invention relate to the provision of means for overcoming defects in switch construction and the provision of novel constructions and combinations of parts as will more fully appear hereafter.

The switches now on the market for electric weldingt machines, with which I am familiar, are, chiefly adapted for eilicient use with currents of less than 100 amperes. When large currents are carried, such for example, as `those above 100 amperes, `the electric contacts are quickly consumed and the switch becomes excessively heated, causing any spring mechanism employed to lose its temper, and ruining the insulating materials used, thereby disabling, the whole switch. Another objectionable feature of most of the switches now on the market is that the same are not inclosed and are therefore very hard on the eyes of the operator because of the constant dashing, .and are also liable to cause fire if any light combustible material happens to be near the flashing contacts.

Another very serious defect with the usual electric Welding switch with which I am familiar is that known as stickingf that is, the contacts under some conditions weld fast together, preventing the switch from breaking the circuit at the proper instant because of which the materials being welded by the machine may be spoiled. By my invention, these objections are overcome and a switch is provided of cheap, simple and rigid construction, which may be used to advantage both `on light and heavy currents with no danger or annoyance from the arcing of the contacts and with no possibility of the latter sticking.

Among the .features of my improved switch it may briefly be stated that rovision is made for moving the movable e ement of the switch into contactvto make the circuit, under the actuation of a spring which is operated b the; operating lever or hand member o thef switch, the movement of the .movable element of the switch in the opposite direction, to break the circuit, be-

ing caused directly by the actuation of the operating lever itself, aided by a strong spring. More broadly, this feature of my invention may be described as the provision of mechanism whereby a certain amount of pressure is applied at the point of contact of the switch elements when the circuit is made, and a greater amount of pressure, such as to prevent the sticking of the contacts, is applied at the point of contact when the circuit is to be broken.

Other features of my invention compri adjustable terminals extending within an inclosing casing, and a member within the casing movable toward and away from the terminals with a substantially straight line motion parallel to the axes of the terminals and carrying a contact plate so mounted thereon as to equalize the pressure between the same and the switch terminals when contact is made therewith.

In order that a clearerA understanding of my invention may be had, attention is hereby directed to the accompanying drawings forming part of this application and illustrating a preferred embodiment of my invention.

In the drawings, Figure l represents a vertical cross-section through a switch construction embodying my invention, Fig.` 2 is a horizontal section taken on line 2;-2 of Fig. 1, and Figs. 3 and 4 are cross-sections taken respectively on lines 3-3 and 4-4 of Fig. 1. A

Referring to the drawings, the casing 1 preferably consists of a metal box formed of stamped steel having flanges at the upper edges thereof for securing thereto the top 2 formed of fiber or other suitable insulat-k When the fiber top.2 is ating material. Y tached to easing 1 by bolts 3 or Aother suitable securing means, the constructionconstitutes a box open at both lends as `shown in Fig. 1. The twf` electrodesl or terminalsv of the switch, 4 and 5 extend inwardly' through two holes rovided therefcnin the liber top 2. The e ectrodes areiirml x held in proper position by cactirgs 6 and preferably of brass which are secured to the top 2. The terminals 4 and 5 are readily lowered into the casing, as they wear away, by adjusting the same by means of the set screws'8, which extend through the holders 6 and 7 and press against the electrodes.

The connecting wires maybe attached tov suitable lugs upon the holders 6 and 7.

The lower contactof the switch cemprises a copper bar 9 which is mounted within the i casing for movement Atoward and away from the terminals 4 and 5, this contact bar 9 being preferablyrso mounted as stated as to cause the pressure between the same and the switch terminals to be equalized when the bar is brought inco-ntact therewith. In

the preferred form of my invention, this is accomplished by mounting bar 9 for a limited rocking movement about a pin 10. This pivot pin 10 extendspthrough a hole in the center of contact bar 9 and is mounted in the two 'prongs of a fork 11 wh1ch are secured upon either side of 'an upright member 12 formed of fiber or other lnsulating material, fork 11 being secured toV the fiber upright 'by suitable means such as bolts 13. -The copper bar 9 is so mounted between the arms of the fork 11 as to per- -mit the sameto swing through a 'small angle from the horizontal before the same comes in contact with the upper edge ofthe upright 12 at either side 'of the pivot 'pin 10.

Upright 12 with its pressure equalizing" contact. plate 9 is moved in a substantially vertical plane n'as stated 'toward and away from terminals 4 and 5 in 'the operation of the switch. Also, as stated, I providelmeans for breaking the Contact 'between bar 9` and the switch terminals under a; pressure sulicientto prevent sticking of the contacts,

while the-mechanism for bringing the con-y tacts together to make the circuit need not cause the exerting of so much pressure atv 'the point of contact between plate 9` and the switch terminals. The preferred means for obtaining these results will now be described.

The operating lever 15, ofthe switch, preferably comprising parallell side portions as shown, isV preferably provided with a handle 16 and is pivoted upon a rod 17 mounted in the sides of the casing 1. A

lever or link 18.is pivotally mounted at one' end upon the-same rod 17 and at its other end upon a rodA 19, which latter extends through the ber upright 12. The operating lever 15 extends for some distance beyond its pivot in the direction of upright 12 as shown, this end of lever 15 normally resting upon a strap .20 formed integral with or secured to link 18 which latter preferably comprises `parallel portions located at both sides of upright 12 as shown.

A lever 21 is mounted on rod 22, which is usupported in holes formed in the opposite side walls of casing 1, lever 2,1 comprising two parallel portions extending on both sides of upright 12-'in the same manner as link 18, lever 21 being secured to the upright 12 vby means of a pin 23 extending through the upright. Lever 21 is parallel to link 18, rods 19 and 23 and 17 and 22 forming the corners of'a parallelogram. The side por tions ofl lever 21 are joined at their rear end by a portion 24 to which is secured preferably by electric welding a cross bar 25 provided at each end with notches for the attachment ofsprings 26. The lower ends of'springs 26 are attached to -lugs at the'ends of a strap 27 secured to and ex tending acrossoperating lever 15 as shown.

` A compression spring 28 is interposed be.-

tween the bottom kof the casing l and the operating lever 15, the upper end of this per bar 9 contacts the lower end of elec-y trodes 4 and 5. This movement of standard 12 and bar 9 is effected Vby means of springs 26 which are extended by the depression of the operating lever and by the oscillation of lever 21 about its pivot caused by the pull thereon of springs 26; The

movement of standard 12 isapproximately i in a straight vertical line because of the fact that link 18 `and Athe lever arm 22, 23 off'lever 21 connected'. to th-standardare parallel and of the same length. When conact is -made between bar 9 and the terminals 4 and 5, the movements of thebar and ofthe other movable parts ofthe switch vcease with the exception of the movement f the operating lever 15 which may be continued until the operating lerer comes in contact with the Yfloorof the switch box. This continuation ofthe movement of the op operating lever after all the other working parte of the switch have stopped causes the' extremities of the operating lever to leave the strap 20 on lever 18, the springs 26 to 13e t,

-be further extended andi spring 28 to be further compressed. The pressure exerted by bar 9 upon terminals 4 and 5, `it will thus be seen,` is entirely independent of the pressure exerted on the operating lever and is wholly governed by the strength of the springs 26. When the operating lever is released, it is forced upwardly by spring 28 and springs 26, lever 15 swinging about its pivot 17 until thc inner ends of lever 15 engage strap 2O on link 18, when the upwardly directed force of spring 28 causes the directfactuation downwardly of'the upright 12 and bar 9, the downward movement of the inner end of lever 15 being transmitted directly and positively to the upright 12 through the engagement of lever 15 with the strap 20 on link 18. This movement is continued until standard 12 comes in contact with the floor of the switch box 1. It should be noted that springs 26 are made strong enough only to insure good contactA between bar 9 and the terminals 4 and 5, whereas spring 28 is made strong enough to exert a considerable force so as to always insure the breaking of the contact between bar 9 and the switch terminals even if the bar and,the terminals should become stuckfor welded together.

It should be noted that the rocking movement of bar 9 a's described enables the latter to equalize its pressure between the terminals 4 and 5 and that the parallel motion given the fiber upright 12 causes a good square contact between the terminals and bar 9. The Aoperating means described permits a greater pressure to be applied rto bar 9 at the point of contact of the same with the switch terminals when breaking the Contact therewith than is applied to bar 9 when contact ismade with the terminals, the force applied at the point of contact in making the connection being no more than is necessary, in accordance with the stren th of springs 2G and the force which may e applied to bar 9 in breaking the contact being positively and directly applied by means of the operating lever and being unlimited in amount so as to insure the breaking of the contact under ail circumstances. The adjustment of the switch contacts should also be noted. Bar 9 may easily be removed and replaced by simply removing pivot pin 10. This provision may be of value since there is considerable wear on bar 9 because of the sparking of the contacts. The terminals 4 and 5 may be easily removed as they Wear away by adjusting them in their respective holders 6 and 7 by means of the set screws.

It should be understood that my invention is not limited strictly t0 the details of construction illustrated and 'particularly described, but that the same is as broad in its scope as is indicated by the appended claims.

Having described my invention, what I claim as new therein and desire to secure by Letters Patent of the United States is:

1. In an electric switch, the combination of switch terminals, means for connecting the same electrically, means for moving said connecting means into operative position, comprising an operatin member and `a spring, and means positively connected to said connecting means, position to be moved by said operating member, upon the opposite movement of the latter, for the positive actuation into inoperative position of said connecting means by said operating means upon breaking the electrical connection, substantially as set forth.

2. In an electric switch, the combination of switch. terminals, a movable member for connecting the same, an operating lever, connections between said member and lever, effective upon actuation of said lever in one direction, for moving said member into connecting position, and. comprising a spring, and connections Vbetween said lever and member, effective upon actuation of said lever in the other direction, for moving said member out of connecting position, substantially as set forth.

3. In an electric switch, the combination of switch terminals, a'movable member for connecting the same, an operating lever, connections between said member and lever, effective upon actuation of said lever in one direction, for moving said member into coni nerting position, and connections between said lever and member, effective only upon actuation of said lever in the other direction, for positively moving said member out of connecting position, substantially as set forth. v

4. In -an electric switch, the combination of stationary means, a member movable into and out of contact therewith, said means and member being arranged to close and open an electricl circuit when in and out of contact respectively, and means for moving said movable member into and out of contact with said stationary means, so arranged that a. greater force is exerted on said movable member at the point of contact of said member and means upon the breaking of such contact, than upon the making of such contact, substantially as set forth.

In an electric switch, the combination of stationary means, a member movable into and out of contact therewith, said means and member being arranged to close and open an electric circuit when in and out of contact respectively, an operating member, connections between said operating member and movable member, effective to operate the latter into contact with Ysaid stationary means upon movement of said operating member in one direction, and comprising a spring, and means positively engaged by said operating member yupon movement thereof in another direction, for moving said movable member out of contact with` open an electric circuit when in and out of y contact respectively, an operating'member, connections between said operating member r and movable member, effective to operate the latter into contact with; said stationary means' upon movement 'of said operating member in one direction, and means for 'applying retraeting pressure upon sai-d movable member, only upon movement of said .operating member-in a dii'erent diicction,

adapted to cause greater force tov'be applied to said movable member in withdrawing the same from contact withjsaid stationary means than Wasexerted upon the same upon its movement into contact with saidl stationary means, substantially as set forth. v

7. In an electric switch, the combination of stationary means, a member movable into and out of contact therewith, said means and member being Varrarnged to close and open an electric circuit when in and lout of contactrespectively, anoperating member, means for causing movement of said operating member in one direction to move said movable member into contact with Vsaid stationary means with no more than a predetermined pressure, and means intermediate said operating and movable members for causing movement of said operating member in a different direction to move said movable member out of such contact with a pressure which may exceed such predetermined pressure, substantially as set forth.

8. In an electric switch, the combination of switch terminals, a member mounted for movement into and out of electrical connectio/n therewith, a` ivoted operating lever, a second lever paral el to the first, connected at one end to said member, and a spring connecting the free end of said second lever with a movable portion of said first lever, substantially as set forth.

9. In an electric switch, the combination of stationary andmovable contact means, an operating lever, an operating connection between said lever. and movable contact means comprising `a lever and a sprin'g connecting said levers, a link pivotally connected to said operating lever and movable Y contact means, and means for operatively connecting said link andA said operating lever when the latter moves in the direction required for breaking Contact between said stationary and movable contact means, substantially as set forth.

J0. In an electric switch, the combination of stationary and movable contact means,

ai; operating lever, an operating connec- Aof stationary and movable contact'` means,

an operatin lever, a member connected to said movab e contact means, and so positionedA as to be contacted ,by said lever on movement of the latter in one direction only, to move said movabie means o ut of contacting osition, and means for mov' said mova le means into contacting .position on movement of said' lever in the opposite direction, substantially as set forth.

12. In an electric switch, the combination of stationary means, a member .movable into and out of contact therewith, `said means and member being arranged to close and open an electric circuit when in and out of'contact respectively, an operating member, a spring connected to said operating member and movable member, adapted to Y l i be extended by movement of said operating member in one direction,l tocause contact between said movable member and stationary means, a stronger spring engaging the operating member and compre by the operative movement of the latter, and means whereby the latter spring becomes effective to move said movable member out et contacting pition when the operating member is` re eased, substantially as set forth.

413. In an electric switch, the combination vof a casing, adjustable terminals extending into 'the same, a movable non-conducting ,member within the casing, means for movon said pin, and adapted -to `swing t 'rough a small angle thereon, said plate extending normally at right angles to the axes of said terminals, and adapted to be brought into contact therewith, 'substantially as set forth.

14. In an electric switch, the combination of a pair of parallel adjustable terminals, an

insulating member, a contact 'plate carried thereby and adapted to be brought into `and removed from contact with said terminals, parallel levers' p1votally connected at one end of each uf the saine to said insulatin This specification signed and witnessed member:i and arrnged bof form a grail this 15th day of June, 1914.

motion eviee an means or o ers. one

of said levers 1|to move seid memEer in ag sub- JAMES H GRAVELL' stantially straight line movement toward Witnesses:

and away from said terminals, substantially JOHN B. KILBUHN, as set forth. WM. J. EAnNsImw.

(10pm of this patent my be obtained for ive cents each. by nddresling' the "ommislloner et Patente. Washington, ID. 0."

It is hereby certified that in Letters Patent No.' 1,200,485, granted October 10, 1916, upon the application of James Il. Gravell, of Philadelphia, Pennsylvania, for an improvement in Electric Switches, an error appears in the printed specification re uirin correction as follows: Pa e 3, lino 74 claim l, for the word osition q g g 1 P read positioned; and that the said Letters Patent should he read with this correo- V tion therein that the same xnayoonform to the record of the oase in the Patent Office.

Signed and sealed this Qthday of January, A. D., 1917.

[SEAL] F. W. H. CLAY,

Acting Commiss'ioncr of Patents. 

